Call-indicating system.



A. E. LUNDELL.

CALL INDICATING SYSTEM.

APPLICATION nuzo NOV. 1. 191a. RENEWED MAR. I3. 1918.

LWQQM, Patented Oct. 1, 1918.

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lm/emor: Alfie/1 E. Lamdel/L A. %E. LUNDELL.

CALL INDICATING SYSTEM.

APPLlCATlON FILED NOV. 1, I916. RENEWED MAR-13,1918.

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A. E. LUNDELL.

CALL INDICATING SYSTEM.

I APPLICATION FILED NOV. 1, I916. RENEWED MAR. 13.1918.

Patentedl Oct. 1,1912%,

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ALBEN E. LUN DELL, OF NEW YORK, N. Y., ASSIGNOR T WESTERN ELECTRICCOMPANY, INCORPORATED, 013 NEW YORK, N. 1 A CORPORATION OF NEW YORK.

CALL-INDI [CATING SYSTEM.

Specification of Letters Patent.

Application filed November 1, 1916, Serial No. 128,874. Renewed March13, 1918. Serial No. 222,241.

To all whom it may concern:

Be it known that 1, Armin E. LUNnELL, a citizen of the United States,residing at New York, in the, county of Bronx and State of New York,have invented certain This invention relates to trunking in telephoneexchange systems, and more particularly to systems in which automaticmeans are provided for informing a final connecting operator of thenumber of the wanted line.

It is the A feature of the invention is an arrangement by which asequence switch rotates through its cycle to send impulses in accordancewith the setting of a register, which may be a'manually adjustedkeyboard, or some type of electromagnetically adjusted switch. p

A further feature of the invention is the utilization of both sides ofthe'trunk for impulse sending, the impulses over one side of the trunkbeing used to operate a step-bystep switch, and the impulses over theother side being used to energize desired ones of a combination oflocking relays, such other side of the line being successively extendedto said relaysby the operation of the stepbystep switch.

The invention has been shown as applied to a telephone exchange systemof'the wellknown semi-automatic type, but is obviously capable ofarrangement for use in other systenis.

It is thought that the invention will best be understood from thefollowing detailed description, reference being had to the accompanyingdrawings.

In the drawings, Figure 1 represents the substation apparatus of acalling subscriber and an A o )erators connectin cord circuit togetherwith a selector switch for extending the calling line to a trunk leadingto a B operators position. In Fig. 2, portions of a connecting circuitat the B operators po sition are shown, together with the substationline and apparatus of a called subscriber. A step-by-step switch whichcontrated.

object of this invention to pro-. vide an improved meansfor informing afinal connecting operator ofthe number of the Wanted line by means ofvisual signals.

trols the call indicating device is indicated in the lower portion ofFig. 2. Fig. 3 represents the A operators sending device and theoperating circuits therefor. In Fig. 4: therelay combination controllingthe lighting of the number indicating lamps is illus- It is to beunderstood that in practice there would be only one sender per operatorsposition, and that this sender would be associated with the proper cordcircuit by means of a cord finder switch. Since this 'arrangementisWell-known in the art, the cord finder has been omitted for the sake ofsimplicity, and it has been assumed that there is a sender in permanentassociation with each cord.

When the subscriber at substation 1 desires a connection, he removes hisreceiver from the hook, causing the display of a line signal 2 'by theoperation of line relay 3 in the well-known manner. The connectingoperator at 0, upon observing the lighted lamp 2, inserts a plug 4 intoa jack 5 associated with lamp 2, whereupon cut-0d relay 6 is energizedover' a'circuit from grounded battery, winding of relay 6, sleevecontact of jack 5, sleeve of plug l,windin of relay 7, to ground. Bela 7-1s energize and completes a circuit or the power magnet 100 of theconnecting cord sequence switch from grounded battery, winding of powermagnet 100, connecting cord sequence switch contact 101, front contactandarmature of relay 7 to ground. The connecting cord seql16IlC6S\V1tCl1 moves from position 1 into position 2, under the control of itsnormal Patented net. 1., acre.

is now completed for relay 8 from grounded battery, winding of relay 8,connecting cord sequence switch contact 107, conductor 108, armature andback contact of the upper 0 counting relay, winding of stepping magnet.109, sender sequence switch Contact 110, conductor 111, to ground atconnecting cord lllliti sequence switch contact 112. Relays 8 and 109are energized in this circuit. Relay 8, at its left-hand armature andfront contact, locks itself to conductor 108 through con- -necting cordsequence switch contact 113,

and at its right-hand armature and front contact, completes a circuitfrom ground, through connecting cord sequence swltch contact 114, formoving the connecting cord sequence switch out of position 2 intoposition 3.

It is to be understood that the operator at 0 has in the meantimeascertained the number of the desired line in the well-known manner. Shethen depressed one of the keys 115, 116, 117, etc., which control thecounting relays, to cause the selector associated with her cord circuitto hunt in a section whose trunks run to the deslred ofhce. She

also depressed a key in each of the sets,

K, K .-It is assumed that the called subscribers number is composed ofonly two digits for the sake of simplicity. It is ob vious, however,that the system could be extended to indicate any desired number ofdigits. v i

Let us assume that the trunks running to the desired office are locatedin the first group of contacts of the selector, and that the number ofthe wanted subscriber is 47.

The operator will then have depressed ofleft-hand armature and frontcontact of relay 8, connecting cord sequence switch contact 123,conductlng segments of a commutator 1:24 and brush 125 to ground. Thisintermittent actuation of relay 109 successively operates the countingrelays in the well-known manner. When the upper counting relay 0 isenergized, the circuit of relay 109 is permanently opened, and whenbrush 125 engages the next insulating segment, the alternate path ofrelay 8 to ground is broken, and this relay also de'e'nergizes. Theenergization of the upper counting relay 0 completes a circuit fromground, right-hand front contact of the upper 0 counting relay, sequenceswitch contact 120, he winding of power magnet 105, to grounded battery,to move the sender sequence switch out of position 3 into position 4. The deenergization of relay 8 completes a circuit from ground, right-handarmature and back contact of relay 8, connecting cord sequence switchcontact 127 and winding of power magnet 100-, "for moving the connectingcord sequence switch out of position '3 and into position 11.

The brush set 122 hunts for an idle trunk to a B operators positionindicated at 0 in a position of the connecting cord sequence switchbetween positions 3 and 11, in the well-known manner,

When the brush set 122 comes to rest on the terminals of an idle trunk,a circuit is completed for relay 128 from ground, winding of relay 128,sender sequence switch contact 129, conductor 111, connecting cordsequence switch contact 130, brush 131, 1361'.- minal. 132,, lowercontact of spring 133, upper left-hand winding of a repeating coil 134,and winding of relay 135 to grounded battery. Relays 128 and 135 areenergized,

.relay 128 closing at its front contact a cirnal 137 is lighted in thiscircuit and informs v the operator that a call is coming in over thetrunk with which such signal is associated. She then depresses the keywhose springs are indicated at 133, 141 and 142, and maintains itdepressed until the light. ing of the number'indicating lamps informsher of the number of the desired line.

When key 133 is operated, battery is removed from conductor 111,, andrelay 128 deenergizes, closing at its armature and'back contact acircuit through sender sequence switch contact 143, for moving thesender sequence switch out of position 4 and into position 5.

When the sender sequence switch arrives in position 5, a circuit iscompleted from ground, sender sequence switch contact 144, impulsesending switch contact 145, winding of power magnet 146 of an impulsesending switch, to grounded battery. This switch, when actuated, rotatesthrough its cycle of positions without stopping until it returns tonormal position. Impulses are sent over the lower trunk conductor fromground, impulse sending switch contact 147, sender sequence switchcontact 148, conductor 108, connecting cord sequence switch contact 149,brush 150, terminal 151 over thelower contact of key spring 141-,left-hand armature and back contact of relay 152, and the winding ofrelay 153, to grounded battery. Impulses are sent over the upper trunkconductor, in accordance with the setting of key sets K and K, overconductor 154,

sender sequence switch contact 155, con- {ductor 111, connecting cordsequence switch contact 130, brush. 131, terminal 132, upper contact ofkey spring 133 and wiper 156 of Y understood, however, that the systemmight readily be arranged for use with any de-- sired number of digits.y

The operation of the indicating device I will now be described.Assuming'that the {will depress key 20 number of the called line is 47,the operator 4 of key set K and key 7 of key set K When the impulse sending switch passes from positions 1%} to 2%, contact'147 'will be closed,completing the previously traced circuit for relay 153. Relay 153 willbe energized and completes a circuit from grounded battery, winding ofstepping magnet 157, wiper 158'and its first contact, armature and frontcontact of relay 153 to ground. The operation of the switch controlledby magnet 157 will b cause wipers 156, 158 and 159 to be ad vanced intotheir second positions. Locking-relay 160 is now connected to the uppertrunk conductor through side-switch wiper 156, but is not energizedsince conductor 154 finds no ground while the-impulse sending switch isassing-through position 2, due to the fact that conductor 161 is notconnected to contacts of key 4 in the, tens group. When the impulsesending switch leaves position 24 relay 153 is denergized, and acircuitis completed from grounded battery,

winding of stepping magnet 157, wiper 158' in its second position,armature and back contact of relay 153'to ground. The stepby-step switchwipers are now moved from position 2 to position 3. When the impulsesending switch passes from positions 3% to 4%, relay 153 is againenergized to advance the step-by-step switch from position 3 to position4. In this, position relay 162 is connected to the upper trunk conductorover side-switch wiper. 156, but is not energized since no ground is puton conductor 154 when the impulse sending switch passes throughposition-4. On leaving position 44, relay 153 is denergize'd and movesthe step-by-step switch into position 5.

When the impulse sendingswitch passes from positions 5% to 6%}, relay153 is again energized-t0 move the step-by-step switch from position 5to position 6. At this time relay 163 is connected to the upper trunkconductor, but is not energized since no ground is put on conductor 154when the impulse sending switch passes through positlon 6. Thestep-by-step switch is moved into position 7, as previously described.

When the impulse sending switch moves through positions 7?; to 84, relay153 is energized to move the step-by-step switch into position 8. Atthis time relay 164 is connected to the upper trunk conductor asdescribed, but is not energized since conductor 154 finds no ground whenthe im pulse sending switch moves through position 8. The step-by-stepswitch is moved into position 9 as before described.

When the impulse sending switch passes from positions 95;- to 102;, thestep-by-step switch is moved into position 10. At this time relay 165 isconnected to the upper trunk conductor and is energized, since conductor154 is grounded when the sending switch passes through position 8 over apath through impulse sending switch contact 166, conductor 167, closedcontact otkey 7 of the set K, to ground. Relay 165 looks itself up overa path from grounded battery, winding of relay 165, its armature anddeft-hand front contact, conductor 168,]

armature and front contact of relay 169, to ground. Relay 169 wasenergized when key spring 142 was closed, over a path from groundedbattery, winding of relay 169, to ground through the-.clOsed contact ofkey.

spring 142. -When the sending switch leaves position 104 thestep-by-step switch is moved into position 11, as reviously described.The step-by-step switch will continue to 'be advanced in the mannerdescribed under the control of contact147. No more of the locking relaysare energized, since conductor 154 fails to find ground when the'impulse sending switch moves through positions 12, 14 and 16.. When thesending switch leaves position 16% the step- I by-step switch moves into.position 17.

At this time a circuit is completed for relay 152 from grounded battery,winding of relay 152, conductor 170,'wiper 159 and its 17th contact, toground. The operatlon or relay 152 opens the circuit. of relay 153 andprevents any difference in potential between the battery of repeatingcoil 188 and the battery at the oiiice at which relay 153 is located,from causing an undesired energization of relay 153, when the connecting.coro sequence switch moves intop'osition 16 as will be later described.

When wiper 159 arrives in position 17, the circuits for lamp 4 of thetens group and lamp 7 of the units group are completed as follows, itbeing remembered that of the locking relays only relay 165 is energized.The circuit of lamp 4 of the tens group extends trom grounded battery,right-hand armature and back contact of relay 164, conductor 171, outerright-hand armature and back contact of relay 163, outer rightand backcontact 0 conductor 172.

hand armature and back contact of relayv- 174, inner right-hand armatureand back contact of relay 175 lamp 7, inner armature f relay 176, togrounded It is to he noted that at this time no other lamps can belighted in the tens group, since the unactuated condition of relay 164prevents battery being supplied to lamps 9, 7,

unactuatedcondition of relay 160 prevents lamp 0 from being lighted.Similarly, in the units group no other lamp than lamp 7 can be lighted,since the actuated condition of relay 165 prevents lamps 0, 1, is, 3 and4 from being lighted; the unactuated condition of relay 174 preventslamp 9 from being lighted; the unactuated condition of relay 175prevents lamps 8 and 6 from being lighted, and the unactuated conditionof relay 176 prevents the lighting of lamp 5. 1

The setting up of any desired number by, means of the lamps may betraced in a manner similar to that above described.

When" the operator at 0 observes the lighting of the numberindicatinglamps,

she releases the key whose springs are indicated at 133, 141 and 142,and the trunk is connected through springs 133 and 141 to the left-handwinding of repeating coil 134.

The opening of the contact controlled by spring 142 results in thedenergization of relay 169, whereupon circuit is completed from groundedbattery, winding of stepping magnet 157, side-switch Wiper 158 in its17th position, to ground through the armature and back contact of relay169. The stepby-step switch makes one step into its normal position,causing the extinguishing of the lamps by the removal of ground fromconductor 172. The step-by-step switch, as

shown in the drawing. shows the wipers ar-' erationwhcrc the impulsesending switcli left position 16. ()n arriving in position 17, a circuitis completed from ground, impulse sending switch contact 17 7, sendersequence a switch contact 178, winding of power magnet 105 of the sendersequence switch, to grounded battery. The sender sequence switch movesout of position 5 into position 1 under the control of its normal spring106. The impulse sending switch continues into position 1 where it comesto rest, since its ground, sender sequence switch contact 180,

conductor 131, connecting cord sequence switch contact 182, winding ofpower magnet 100 of the connecting cord sequence switch, to groundedbattery. The connecting cord sequence switch then moves from position 11into position 16 under the control of its normal spring 102. In osition16 the talking strands of the cord s own at 0 are connected tothebrushes 131. and 150 cord sequence switch tion ofthis operation,assuming that the line was idle, a circuit is completed for relay .139from grounded battery, lamp 137, relay 139, sleeve of plug 183, sleevecontact of jack 184, and the winding of cut-ofl' relay 185, to ground.Relays139 and 185 are energized, relay 1.85 removing the control of theline signal from the called subscriber in the well-known manner. Relay139 at its upper armature and front contact connects the upper talkingconductor of the connecting cord'to the tip conductor of plug 183. Atits lower armature and front contact relay 139 completes a lockingcircuit for itself, from grounded battery, resistance 186, lowerarmature and front contact of relay 139, armature and front contact ofrelay 135, conductor 138, winding of relay 139, sleeve of plug 183,sleeve contact of jack 184. and the winding of cut-off relay 185, toground. Since coil 186 is of comparatively low resistance, it shuntsoutlamp 137. Relay 135 is held energized at this time over a path fromgrounded battery, winding of relay 135, upper left-hand winding ofrepeating coil 134, lower contact of key spring 133, upper trunkconductor, terminal 132, brush 131, connecting cord sequence switchcontact 187, and the upper right-hand winding of repeating coil 188, toground.

The insertion of plug 183 into jack 184 and the subsetpient response ofthe called subscriber, completes a circuit for supervisory relay 189over the called subscribers line in'the usual manner. The operation ofrelay 189 completed a circuit for a supervisory relay 190 over a circuitfrom grounded battery, lower right-hand winding of re peating coil 188,windingof supervisory relay 190, connecting cord sequence switch contact191, brush 150, terminal 151, lower trunkconductor, upper contact of keyspring 1 11, lower left-hand winding of repeating coil 134, impedancecoil 192, to ground through the armature and front contact of relay 189.The connection is now complete and the subscribers may converse.

At the conclusion of the conversation, after both parties have replacedtheir receivers, relay 189;will be deenergized, due to the hangingrup ofhis receiver by the called party. his 189 results in the deenergizationof supervisory relay 190. The hanging. up of the calling partys receiverresults in the deenergization of relay 193. The lighting of theWelLknown supervisory lamps (not shown) at the operators positionindicated at 0, informs the operator that connection is no longerdesired and she removes plug 4 from jack 5, whereupon relay 7 isdeenergized. The deenergization of relay 7 completes a circuit fromground, armature and back contact of relay 7-, connecting cord sequenceswitch contact 194, winding of power magnet 100, to grounded battery,for moving the connecting cord sequence switch out of position 16 andinto position 18.

In position 18 of the connec'tingcord sequence switch, a circuit iscompleted from grounded battery, winding of power magnet 195, connectingcord sequence switch contact 196, to ground. Brush set 122 is returnedto normal position under the control of a constantly rotating roller197. When brush 125 engages segment 198 a circuit is completed fromground, brush 125, segment 198, connecting cord sequence switch contact199, and the winding of power magnet 100, to grounded battery, formoving the connecting cord sequence switch out of position 18 and intoposition 1. As soon as brush set 122 moved off the terminals of thetrunk over which the connection is established, the circuit of relay 135is broken and the shunt circuit about lamp 137 is removed.

The resultant lighting of lamp 137 informs the operator at 0 and sheremoves plug 183 from jack 18 1. The apparatus has now all been restoredto normal and is ready for reoperation. I

Referring to that point of the operation at which the operator at Oinserted plug 183 into jack 184, it will be noted that if the calledline is busy, the operator will receive a click in the receiverindicated at 200, due to the presence of potential on the sleeveconductor of jack 184:. This potential will be sup-plied from groundedbattery, either through lamp 137 or through resistance 186, and when thetip of plug 183 endeenergization of relay over said trunk line, anindicatin system, calling and called lines, a final conneoting operatorsposition, a trunk line,

means for extending a calling line to said operators position oversaidtrunk line, an

indicating device for displaying the number of a called line at saidposition, means to simultaneously send impulses over both sides of saidtrunk, a step-by-step switch operated by impulses over one side of saidtrunk, and a combination of locking relays to control said indicatingdevice, desired Ones of said relays being energized by impulses over theotherside of said trunk.

2. In a multi-oflice telephone exchangesystem,'calling and called lines,a final connecting operators position, a trunk line, means for extendinga calling line to said operators position over said trunk line, an

indicating device for displayin the number of the called line at saidposition, means to simultaneously send impulses over'both "sides of saidtrunk, a step-by-step switch operated by impulses over one side ofsaidtrunk, and a combination of locking relays to control said indicatingdevice, desired ones of said relays being energized in correspondingpositions of said switch by impulses over the other side of said trunk.

3. In a multi-ofiice telephone exchange system, balling and calledlines, a final connecting operators position, a trunk line, means forextending a calling line to said operators position over said trunkline, an indicating device for displaying the number of the called lineat said osi'tlon, means to simultaneously send impul es over both sidesof said trunk, a step-by-step switch operated by impulses over one sideof said trunk, a set of fixed contacts arranged for engagement by awiper of said switch, and a looking relay associated with each of saidfixed contacts, said relays being arranged to be energized by impulsesover the other side of said trunk.

4, In a multi-oflice telephone exchange system, calling and calledlines, an A operators position, a B operators position, a trunk line,means for extending a calling line tosaid B operators position devicefor displaying the number of the ca led line at said B operatorsposition, a key set at said A operators position, means tosimultaneously send impulses over both sides of said trunk, astep-by-step switch operated by impulses over one side of said trunk,and a combination of locking relays to control said indicating device,desired ones of said relays being energized by impulses over the otherside of said trunk in,

accordance with the setting of said key set.

.5. In a multi-oflice telephone exchange system, calling and calledlines, an A operators position, a key set thereat, a B operatoflsposition, a trunk line, means to extend a calling line to said Boperators position over said trunk line, an indicating device fordisplaying the number of the called line at said B operators position, amulti-position sending switch at said A operators position, meansincluding said switch to simultaneously send impulses over 0th sides ofsaid trunk, a step-by-step switch operated by impulses over one side ofsaid trunk, and a combination of relays to tion, said switch beingar'anged to move through its cycle of positions and return to normalwithout stopping when moved out of normal, means including said switchto simultaneously send impulses over both sides of said trunk, astep-by-step switch operated by impulses over one side of said trunk,and a combination of relays to control said ma am a signaling device,means for simultaneously sending impulses over both of said conductors,a step-by-step switch operated by im pulses over one of said conductors,and a combination of locking relays arranged to be operated by impulsesover the other conductor to selectively operate said signaling device.

8. In a telephone system, two conductors, a signaling'device, means forsimultaneously sending impulses over both of said conductors, astep-by-step switch operated by impulses over one of said conductors, aset of fixed contacts arranged for engagement by a wiper of said switch,and a relay associated with each of said fixed contacts, said relaysbeing arranged to be operated by impulses over the other conductor toselectively operate said signaling device.

9. In a telephone system, two conductors, a signaling device, meansforsimultaneously sending impulses over both of said conductors, amanually operable device for varying the number of impulsessent, astep-bystep switch operated by impulses over one of said conductors, anda combination of relays for controlling the operation of said signalingdevice, said relays being arranged to be operated by impulses over theother conductor in accordance with the operation of said manuallyoperable device.

In witness whereof, I hereunto subscribe my name this 30th day of@ctober A. D, 1916.

ALBEN E. LUNDELL.

